Method of producing moisture resistant building units



July 4, 1961 R. E; PARKER 2,991,190

METHOD OF PRODUCING MOISTURE RESISTANT BUILDING UNITS Filed Dec. 16. 1957 POLYVINYL CHLORIDE POLYVINYL ACETATE COPOLYMER PLASTICIZER POLYVINYL ACETATE POLYVINYL CHLORIDE POLYVINYL ACETATE COPOLYMER COLORING PIGMENT Fig.1. ALUMINUM SILJCATE DISPERSION AND SUSPENSION AGENT STABILIZER POLYVINYL CHLORIDE POLYVINYL ACETATE COPOLYMER I l III I/III/III IIIIII POLYvINYL ACETATE POLYvINYL CHLORIDE POLYVINYL ACETATE COPOLYMER NTOR; COLORING PIGMENT Ralph E. Parker ALUMINUM SILICATE BY DISPERSION AND SUSPENSION AGENT I STABILIZER I, ATORNEYS U lf This invention relates to the field of building construction and more particularly to a method of producing building units having special utility as weatherproof siding and roofing adapted to be placed on the external surfaces of buildings.

Various types of siding and roofing have been suggested in the past and which were successful in some applications, but the prior materials have not been entirely successful because the same could not be partially or entirely submerged in the ground, nor were they completely water impervious while retaining insulating characteristics and available at low cost. The heretofore suggested siding units have included those provided with indentations in one surface thereof to simulate masonry, but these units have been coated or impregnated with asphaltic or bituminous substances to render the same substantially moisture resistant and thus, inherently defective because the substances did not adequately resist wide temperature differentials and were subject to weathering. Asbestos type siding has not been successfully developed to a uniformly acceptable product because of the fact that siding of this character is very easily cracked and is subject to fading because of poor weathering properties. Siding such as aluminum is not only prohibitively expensive but also subject to denting by various objects including hail and, for appearance purposes, must be painted with pigmented oil paints, thus increasing the cost of application and necessitating frequent repainting. Wooden siding has remained the most popular over the years because of the relatively low initial cost but, again, it is to be pointed out that siding of this type must be frequently repainted and deteriorates rather rapidly, especially in those climates where the same is subjected to extreme weather conditions. Furthermore, wooden siding does not have the inherent insulating properties of other materials and thus, secondary insulation must be used between the framework for the building and the wooden siding in order to provide sufficient prevention of heat transfer between the interior of the building and the ambient atmosphere.

It is, therefore, the most important object of this invention to produce a building unit particularly adapted for application to the exterior of a building which is constructed in a novel manner so as to be substantially moisture impervious and capable of being submerged in the ground while retaining its insulating properties so that, for the most part, secondary insulation is not necessary.

Also an important object of the present invention is to provide a method of producing a building unit as described wherein a rigid, relatively porous fiberboard having high insulating properties is completely encased within a continuous, substantially moisture impervious envelope formed of synthetic resin material whereby, upon application of the units to the exterior of a building, heat transfer and passage of moisture through the units from the building or the ambient atmosphere is effectively prevented.

Also an important object of the invention is to provide a method of producing building units as referred to above wherein the fiberboard is encased within successive layers of inert, organic, film forming materials to render the board substantially moisture impervious and of a suitable color so that application of an external paint to the siding after emplacement of the same on the exterior of a building is unnecessary.

Other objects of the present invention relate to the States Patent Patented July 4, 1961 provision of a method of producing a building unit Wherein a series of channels are formed in one face of the fiberboard prior to application of the film forming material to the outer surfaces thereof so that the board thereby simulates a preselected masonry pattern; to the provision of a method of repairing building units constructed in a manner as described above by applying an additional amount of the film forming material to those portions of the fiberboard which are substantially exposed during application of the coated fiberboard to the exterior of a building; to the provision of a method of filling the masonry simulating channels of the coated fiberboard with a plastic type cement which renders the building unit very similar to specified masonry construction appearancewise; to the provision of a method wherein the final film coating is embossed prior to drying of the same so that the exteriorly exposed surface of the coated fiberboard more nearly corresponds to the desired masonry finish which the same is simulating; to the provision of a building unit constructed in accordance with the novel method set forth above; and to other lesser important objects which will become obvious as the following specification progresses.

Referring to the drawings,

FIGURE 1 is a cross sectional view of a building unit coated with coatings of the invention; and

FIGURE 2 is a cross sectional view of a building unit with coatings of the invention thereon and masonry channels filled.

Briefly, the present invention contemplates successively applying a plurality of organic, inert, film forming materials to the outer surfaces of a rigid, relatively porous fiberboard having insulating properties, to completely encase the board within a continuous, substantially moisture impervious, laminated envelope having good weathering characteristics capable of withstanding wide temperature differentials and thereby particularly adapted to be utilized as an external protective covering on buildings either as siding or roofing. One face of the outer surface of the fiberboard may be grooved in a suitable manner to present a series of channels corresponding to a defined masonry simulating pattern so that upon securing of the panels to the side of a building, the coated sheathing presents the appearance of a preselected masonry construction.

The present invention is particularly adapted for coating of high density wood pulp or fiberboards which are relatively porous in nature and have high insulating properties. Sheathing of this character is ordinarily commercially available in designated sizes and of different thicknesses. Although it is not intended to be limited to one specific type of material, the preferred construction member or panel has been found to be a product of the Insulite division of Minnesota and Ontario Paper Company, which is marketed under the trade name of Gray Lite XXX Sheathing and which has the following physical characteristics:

Density 23 lbs/clLft.

Transverse strength 26 in. lbs.

K factor .41.

Tensile strength 550 lbs/with machine, 450

cross. Permeability L. 25 perms or less. Linear expansion RH 50% to 22%.

If it is desired that the final product simulate masonry construction, one face of the fiberboard is routed out to present a series of channels corresponding to a defined masonry simulating pattern. For example, the channels in the outer face of the fiberboard may be formed to present a series of bricks separated by the grooves in the 'board. Because of the fibrous nature of panels of this character, routing of the board leaves the outer surface thereof relatively rough, particularly in the areas adjacent the routed channels, and therefore, if desired, such roughened surface of the board may be subjected to a suitable sander to thereby smooth the edges of the board defining the sides of the channels. However, in some applications, particularly in the formation of panels simulating rough brick, it is desirable to direct the roughened boards to the subsequent coating operations as the same come from the routers because of the fact that the roughened surfaces of the board more nearly simulate actual brickwork.

The grooved fiberboards or, in the alternative, smooth, unchanneled boards which may be either in the form as produced commercially or in elongated strips similar in dimensions to standard wooden lap siding, are next directed to coating apparatus for application of the materials rendering the fiberboards moisture impervious and capable of withstanding wide temperature differentials and sub mergible in the ground. Although the film forming materials to be hereinafter described may be applied in various ways, the preferred method of application will be set forth initially. Each of the fiberboards is attached to a suitable conveyor system which directs the boards along a preselected path of travel and, through suitable cam actuated mechanism, successively lowers each of the boards into a vat containing the initial coating material. Again it is to be pointed out that various substances and in particular synthetic resin compositions may be employed as the initial coat on the fiberboard, but the preferred material is an emulsion of polyvinyl acetate in water and containing approximately 55% solids, a suitable product being Tite-Crete, produced by Surface Engineering Co., Inc., Wichita, Kansas. If desired, a dispersing agent, any of those well known in the art being utilizable, may be incorporated into the emulsion but it is to be emphasized that the organic, inert, film forming material should be non-reversible and therefore, not emulsifiable by moisture once the same has been cured. The quantity of water in the emulsion will vary with the circumstances and those skilled in this art may readily reduce the emulsion to dipping viscosity by carefully controlling the amount of water admixed with the film forming resin. The amount of water in the emulsion should be correlated so that when the material is at room temperature, a coating of from 1 to 2 mm. of the material should adhere to the outermost surfaces of the board.

Although other coating compositions may be utilized to initially coat the outer surfaces of the fiberboard, the water emulsion described above has been found most satisfactory because this material effectively seals the outer pores of the fiberboard without completly impregnating the sheathing. It can be readily appreciated that if a film forming material dissolved in a highly volatile solvent were used, this type of material would tend to penetrate deeply into the pores of the sheathing, thereby increasing the overall cost of the operation because of the amount of material retained within the board after dipping thereof, and also because of the fact that such deep penetration would tend to leave the outer pores of the board open instead of completely sealing the same as the preferred material does thereby rendering the panel substantially moisture impervious after one dipping operation. The preferred polyvinyl acetate emulsion material set forth above has a minimum softening point within the range of 200 F. to 225 F. and therefore, is capable of withstanding relatively wide temperature differentials without any deleterious efiects resulting from such changes in temperature.

After removal of theboard from the first vat by suitable cam mechanism, the board is directed through a drying zone which is maintained at a suitable temperature to cause the polyvinyl acetate material to set up to a sufiicient extent so that the panel may be dipped into the second film forming material hereinafter described. In most instances the first film forming material will set up within 10 minutes at room temperature and therefore, the speed of the conveyor as well as the temperature within the first drying zone may be varied according to the particular specifications for the material utilized.

The sanding operation referred to above may be carried out after the initial dipping operation if desired in order to assure that the final product presents a smooth appearance, if such is necessary to simulate the final product desired.

Next, the board which is encased within the first synthetic resin envelope is dipped into a second vat by suitable mechanism and which is adapted to form a second continuous coating over the polyvinyl acetate material. The preferred composition within the second vat is a low molecular weight resin comprising a copolymer of polyvinyl chloride and polyvinyl acetate, the chloride derivative being present in the range of 93% to 96% and reduced to dipping viscosity by a suitable organic solvent which, in the preferred form of the invention, is methyl isobutyl ketone. The most suitable polyvinyl chloride-polyvinyl acetate resin is a product supplied by Surface Engineering Co., Inc., Wichita, Kansas, under the trade name Secoton Hi-Build. A plasticizer may be incorporated into the second film forming material is desired, and the best results have been obtained by utilizing a phthalate plasticizer in amounts not greater than 3% of the total weight. The quantity of methyl isobutyl ketone utilized will vary with the various immersion conditions, but should be regulated so that at room temperature, a coating of the second material will be formed over the first material to a depth of approximately 1 mm.

The board, after removal from the second vat, is passed through a second drying zone which is again maintained at a suitable temperature to set the second film forming material to a sufficient extent so that the coated board may be subjected to another coating operation. The temperature of the second zone and the time during which the board is maintained within such zone will vary with the material and forced air may be employed to hasten such drying if desired. The particular manner in which the film forming substances are dried forms no part of the instant invention, although it can be recognized that suitable drying ovens may be employed and which utilize electric elements at specified temperatures, and in particular at approximately F. Maintenance of the drying zones at this temperature has been found to materially decrease the drying cycle of the present process and thereby make it possible to direct a greater quantity of boards through the processing apparatus within a designated period of time.

After setting of the second material which encases and completely covers the first material, the board is subjected to a color coating operation and in this respect it has been found that it is more advantageous to spray the color coat onto the panel rather than dipping the same as heretofore described. The color coat is especially formulated to place a permanent fade and weather resistant exterior color on the board, and the preferred composition includes a synthetic resin mate rial comprising a copolymer of polyvinyl chloride and polyvinyl acetate, the chloride derivative being present in the range of 93% to 96% (Secoton Hi-Build, Surface Engineering Co., Inc., Wichita, Kansas), from 20% to 22% by volume of the solid contents of polymeric and phthalate plasticizers, approximately 38% of a filler or film building component which preferably is aluminum silicate, approximately 12% of a dispersion and suspension agent such as Bentone 18-C, produced by National Lead Products Co., 3% to 4% of stabilizers and in particular an admixture of Dyphos and .Plumb-O-Sil-C, also marketed by National Lead Products Co., and up to or more of a suitable pigment color as well as relatively volatile, organic solvents Which are introduced in suificient quantities to reduce the solid components to a sprayable viscosity. An admixture of methyl ethyl ketone, methyl isobutyl ketone and toluol is preferred, and the exact proportions are dependent upon the components used in the above formulation.

The boards should be passed through a suitable spray booth so that the third color coat is uniformly applied to the surface presented by the second material, and it is to be pointed out that the final coat should be applied to a sufiicient extent to completely encase the board and thereby the first and second coats within a third, substantially moisture impervious envelope. The triple-coated board or panel is then directed to a third drying zone Where the materials are thoroughly dried for subsequent passage to the packaging and distribution area. If desired, the board may be passed through an embossing machine while the final or color coat is still somewhat Wet to thereby emboss one face of the coated panel in a suitable manner so that the same more nearly simulates the desired masonry construction.

If the coated board has been routed so that the same simulates brickwork, is is preferred to fill the channels presenting the bricks with a suitable mortar-like substance so that the final product more nearly resembles actual brick construction. The preferred formulation which is adapted to be introduced in the channels simulating the brickwork is an admixture containing one part by weight of Tite-Crete, defined above, three parts by weight of sand, one part by Weight of Portland cement, four parts by volume when dry of a diatomaceous silica, and sufiicient Water to give the admixture proper consistency for use in an injection gun. The diatomaceous silica is of the dry uncalcined type having the following chemical analysis:

It has a refractive index of 1.46, a specific gravity of 2.0, brightness of 76, surface area of 2025 sq. m./gm., and a pH of 8. One source of this silica material is the White Cliffs area of New Mexico.

Mortar prepared in this manner and introduced into the brick simulating channels of the fiberboard strongly adheres to the plastic coating on the surface of the board and will not become dislodged therefrom during subsequent use of the board. It should, however, be noted than the routed portions of the board adjacent the outer peripheral edge thereof are not initially filled with the mortar so that the panel may be nailed in position with the fasteners being driven through these unmortared portions of the coated panel.

Building units constructed in accordance with the method described above are particularly adapted to be secured to the exterior of a building, particularly as siding or roofing. The panels may be readily nailed in the desired position and then the nails countersunk and the holes filled with suitable mortar prepared as described above, or with liquids similar to the first and third compositions herein described and which may be supplied with the boards to the applicator.

However, with the coated fiberboards having a brick simulating pattern in one face thereof, it can be appreciated that the same are secured to the exterior of the building by driving nails through the above described unmortared, routed portions adjacent the outer periphery thereof. Thus, after two adjacent panels have been placed in position, the applicator may subsequently inject a sufiicient quantity of the mortar set forth above into the routed portions of the board through which the nails are driven to thereby give the completed structure the desired-masonry simulating appearance. It is manifest that the final application of the mortar in the routed portions of the board adjacent the periphery thereof also serves to cover up the nail holes and thereby render the entire structure moisture impervious while the insulating properties thereof are retained.

Because of the fact that the fiberboards coated in accordance with the present method may be partially'or completely submerged within the ground, inasmuch as the materials employed have good bacteriostatic and fungistatic properties, it is to be pointed out that the present units thereby present a method of covering up unsightly foundations and the like by securing masonry simulating units fabricated as described above over the old foundation to a depth slightly below the ground level. If the unsightly foundation is of sufiicient height above the ground that it is not practical to secure the coated units directly to the foundation, firring strips which have been coated in a manner similar to that described herein may be suitably secured to the foundation and extend into the ground so that the brick or masonry simulating, coated panels may be subsequently secured to the coated firring strips. The present invention also is of extreme utility because the uppermost ends of the coated panels may be positioned on a horizontal line, even though the building upon which the same are being secured has settled in the center thereof, because of the fact that the panels may be partially submerged in the ground if necessary and thus precluding the necessity of disposing the external panels above the ground, which would tend to emphasize the uneven condition of the lowermost part of the building.

During application of coated panels constructed as outlined above, if it becomes necessary to cut portions of the panels so that the sheathing will fit around windows, doors and similar openings, the exposed severed edges of the panels which thereby present an exposed portion of the fiberboard may be covered by brushing onto such exposed surfaces the first film forming material which is contained in the first va-t and then, after drying of this coating, applying a color coat similar to that applied to the fiberboard in the above defined spray booth. Mani festly, these materials may be supplied to the applicator when he purchases the coated panels, so that the exposed edges of the fiber sheathing may be quickly and easily repaired as the boards are secured in place on the building. Because of the fact that the color coat renders a repaired area substantially indiscernible, the overall appearance of the coated panels is in no way affected by repair operations as described.

Inasmuch as the present building units retain their insulating properties, secondary insulation between the framework of the building and the exterior sheathing is, for the most part, unnecessary, thereby reducing the ovc-rall cost of the building as well as the time necessary to construct the same. Although the preferred process has been set forth herein, it can be appreciated that various modifications may be made without departing from the spirit of the invention and therefore, it is intended to be limited only by the scope of the appended claims.

Having thus described the invention What is claimed as new and desired to be secured by Letters Patent is:

1. In a method of producing a building unit, the steps of applying to the entire outer flat surfaces and edges of a high density, relatively porous fiberboard sheathing having high insulating properties and of substantially greater length and width than thickness, a sufficient quantity of a film-forming material consisting essentially of polyvinyl acetate, to at least seal the outer pores of said sheathing; and then completely encasing the sealed sheathing in at least one continuous, unbroken, moisture impervious envelope of a synthetic resin substance comprising a copolymer of a relatively high proportion of polyvinyl chloride and a substantially lesser amount of polyvinyl acetate.

2. A method as set forth in claim 1 wherein said material is applied as a Water emulsion containing approximately 55% solids.

3. A method as set forth in claim 1 wherein said copolymer of polyvinyl chloride and polyvinyl acetate is applied in a volatile organic solvent present in sufficient quantity to reduce the solution to dipping viscosity.

4. A method as set forth in claim 1 wherein a color coat is applied to said envelope encasing the sheathing, said color coat comprising an admixture of a copolymer of a relatively high proportion of polyvinyl chloride and a substantially smaller amount of polyvinyl acetate, a plasticizer, a film building component, a dispersing and suspension agent, a stabilizer, and a color pigment.

5. A method as set forth in claim 4 wherein said material and the envelope are applied by dipping the sheathing in respective solutions, while the color coat is sprayed over said envelope, the sheathing being passed through a drying zone after application of each of the layers thereto.

6. A method as set forth in claim 1 wherein is included the step of forming a series of channels in one major face of the sheathing, corresponding to a defined masonry simulating pattern, and prior to application of said film-forming material to the sheathing.

7. A method as set forth in claim 6 wherein is included the step of filling said channels, after application of said copolymer to the sheathing, with a composition including an admixture of polyvinyl acetate, sand, Portland cement and diatomaceous silica.

8. A method as set forth in claim 1 wherein one face of the final coating of synthetic resin substance on said sheathing is embossed prior to drying of said final coating to present a masonry defining pattern.

References Cited in the file of this patent UNITED STATES PATENTS 1,624,379 Abbott Apr. 12, 1927 1,721,367 Barringer July 16, 1929 2,230,876 Wysong Feb. 4, 1941 2,292,118 Guhl Aug. 4, 1942 2,300,373 Stoner et a1. Oct. 27, 1942 2,311,589 Feder Feb. 16, 1943 2,491,487 Faulwetter Dec. 20, 1949 2,549,516 Parry Apr. 17, 1951 2,628,948 Kunz et al. Feb. 17, 1953 2,654,687 Fridolph Oct. 6, 1953 2,734,831 Larson Feb. 14, 1956 2,772,986 Buck Dec. 4, 1956 2,776,914 Faulwetter Jan. 8, 1957 2,855,327 Gilchrist et al Oct. 7, 1958 

1. IN A METHOD OF PRODUCING A BUILDING UNIT, THE STEPS OF APPLYING TO THE ENTIRE OUTER FLAT SURFACES AND EDGES OF A HIGH DENSITY, RELATIVELY POROUS FIBERBOARD SHEATHING HAVING HIGH INSULATING PROPERTIES AND OF SUBSTANTIALLY GREATER LENGTH AND WIDTH THAN THICKNESS, A SUFFICIENT QUANTITY OF A FILM-FORMING MATERIAL CONSISTING ESSENTIALLY OF POLYVINYL ACETATE, TO AT LEAST SEAL THE OUTER PORES OF SAID SHEATHING, AND THEN COMPLETELY ENCASING THE SEALED SHEATH- 